Electrolytic Titanium Refining via Molten Calcium Chloride
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Solution Overview
Problem
Existing methods for refining metals like titanium from ores containing high levels of impurities, such as calcium oxide and iron oxide, are inefficient and require high temperatures, making them impractical for large-scale commercial production.
Innovation Solution
The method involves forming a metal oxycarbide by electrolytically reducing a mixture of the metal oxide and carbon in a molten calcium chloride electrolyte, followed by electrolysis of the oxycarbide to produce refined metal at the cathode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional carbo-chlorination process is used to produce titanium chloride from impure titanium dioxide, then high purity titanium can be produced, but the process requires high temperatures and becomes impractical when ores contain significant calcium oxide or fine particles
Solution Approach 1:
The patent changes the chemical parameters of the process by using electrochemical reduction in molten calcium chloride instead of carbo-chlorination. This allows processing of ores containing calcium oxide and fine particles that would be unsuitable for conventional high-temperature carbo-chlorination processes, while still achieving high purity titanium production
Solution Approach 2:
The patent introduces molten calcium chloride as an intermediary medium to facilitate the electrochemical reduction of titanium oxide. This intermediary allows the process to handle impure feeds containing calcium oxide and fine particles, converting them into high purity titanium through selective electrochemical reactions rather than requiring high-temperature carbo-chlorination
2Manufacturing precision
If high temperature processing is used to treat impure metal ores, then metal extraction can be achieved, but the operational temperature requirements increase and processing time extends
Solution Approach 1:
The patent replaces thermal-mechanical processing (high-temperature carbo-chlorination and distillation) with an electrochemical system. By using electrical energy to drive the reduction reactions in molten calcium chloride, the process achieves high purity metal extraction at lower operational temperatures, eliminating the need for extreme heat treatment
Solution Approach 2:
The patent changes the energy parameter from thermal to electrical, using electrochemical reduction instead of thermal reduction. This allows the process to operate at lower temperatures while maintaining high purity metal production, directly addressing the contradiction between temperature requirements and manufacturing precision
3Productivity
If conventional electrochemical reduction is used on impure ores, then metal can be produced, but impurities are not selectively removed and the final product reflects the impurity composition of the original feed
Solution Approach 1:
The patent applies local quality by creating different chemical environments at different locations in the electrochemical cell. The molten calcium chloride electrolyte provides a selective environment where calcium oxide impurities dissolve and are removed, while titanium oxide is reduced to high purity metal at the cathode, achieving both productivity and manufacturing precision simultaneously
Solution Approach 2:
The patent converts the harmful effect of calcium oxide impurities into a beneficial process feature. Instead of calcium oxide causing de-fluidisation problems in conventional processes, the electrochemical process in molten calcium chloride uses the calcium oxide to create a selective dissolution environment that purifies the titanium product while maintaining high productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the operational temperature requirements, allows for quicker formation of the oxycarbide, and results in a refined metal with significantly lower impurity levels, achieving purity of at least 99.5% by weight.
Implementation Method 1
forming a metal oxycarbide by electrolytically reducing a mixture of the metal oxide and carbon in a molten calcium chloride electrolyte
Implementation Method 2
followed by electrolysis of the oxycarbide to produce refined metal at the cathode
Data Source
AI summary
A method of refining a metal (e.g. titanium), comprising the following steps: (a) providing (10) an oxide of the metal having a level of impurities of at least 1.0 wt %; (b) reacting (12) the oxide of the metal to form an oxycarbide by providing an electrode comprising the oxide of the metal and carbon, and electrolytically reducing the electrode in a molten calcium chloride electrolyte; (c) electrolysing (14) the oxycarbide in an electrolyte, with the oxycarbide configured as an anode; and (d) recovering (16) a refined form of the metal from a cathode in the electrolyte.